Did my reply imply as much? I don't think they are issues - that's why I was asking. After bitserve, fluidjax too pointed out the meaninglessness of focusing on 51% attacks as segwit-specific attack vectors.

Fungibility isn't a real issue, either - still IMHO. As SW transactions become the majority, only old or newborn coins will be left in your Type 1 (coins that were never touched by a SW transaction). Besides, LN acts as a kind of giant mega-tumbler. If/when LN really gets into widespread use, it will only help fungibility rather than undermine it.